<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        
    </style>
</head>
<body>
    
</body>
<script>

    // [object Object]：Object对象
    var obj = new Object();
    obj.name = "admin";
    console.log(obj);
    console.log(typeof obj);
    console.log(Object.prototype.toString.call(obj));

    console.log( 1 + obj );



    // [object String]：String对象
    var str = new String("hello");
    console.log(str);
    console.log(typeof str);
    console.log(Object.prototype.toString.call(str));

    console.log( 1 + str );



    // [object Number]：Number对象
    var num = new Number(365);
    console.log(num);
    console.log(typeof num);
    console.log(Object.prototype.toString.call(num));

    console.log( 1 + num );



    // [object Array]：Array对象
    var arr = new Array(3,6,9);
    console.log(arr);
    console.log(typeof arr);
    console.log(Object.prototype.toString.call(arr));

    console.log( 1 + arr );



    // ......

    // [object Undefined]
    console.log(Object.prototype.toString.call(undefined));
    // [object Null]
    console.log(Object.prototype.toString.call(null));



    // 构造任何函数（new执行任何函数），得到的都必然是对象
    // 只是会保留原有数据的特点


    // 万物皆对象
</script>
</html>